public class exer {
    public static void main(String[] args) {
        Person1 P1 = new Person1();
        System.out.println("p1 的信息 name=" + P1.name + " age=" + P1.age);
        Person1 P2 = new Person1("jack",20);
        System.out.println("p2 的信息 name=" + P2.name + " age=" + P2.age);
    }
}
class Person1{
    String name;
    int age;
    public Person1(){
        age = 18;
    }
    public Person1(String pName, int pAge){
        name = pName;
        age = pAge;
    }
}